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I have a Macbook Pro 15" i5, and I'm connecting it to a Samsung 40" 1080p monitor.

Previously, it displayed a 1920x1080 resolution just fine, but then I accidentally changed something in the OSX Display preferences, and the monitor is unable to display 1080p; it only displays resolutions of 1600x1200 and below.

When I select 1920x1080 the monitor displays the message "mode not supported."

I think I messed up by changing the rotation of the external monitor to 270 or something; I tried restoring the default values, but it still doesn't work.

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Have you tried unplugging the monitor from the computer and plugging it back in? Also, can you tell us exactly what you've selected in System Preferences-> Displays for the external monitor? –  Nathan Greenstein May 9 '11 at 0:08
Yes, I've tried that, but it still didn't work. I'm not sure, I think I changed the rotation of the Samsung monitor in the System Preferences-> Displays when it was in 1920x1080 to 270, then it stopped working in that resolution. I also tried reverting back to default rotation, but it still doesn't work. –  radiodio May 9 '11 at 0:09
@radiodio Gotcha. Can you tell us exactly what the settings are that you're using now? –  Nathan Greenstein May 9 '11 at 0:17
@nathan on the Samsung: Refresh Rate is 60hz; Resolution is 1920x1080. edit: I was able to fix it by deleting com.apple.windowserver.plist and com.apple.preference.displays2. Then switching on "Mirror Displays", lowering the resolution, turing off "Mirror Displays", than selecting 1920x1080 again. Thanks for your help, Nathan :-) –  radiodio May 9 '11 at 0:30
@radiodio You should post your solution as an answer to this question so it can help people searching for answers to this problem in the future. –  Austin May 9 '11 at 2:01

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